The present invention relates to an ultrasound probe and an ultrasound diagnostic apparatus, and in particular, to an ultrasound probe and an ultrasound diagnostic apparatus for performing both production of a B-mode image and production of a sound speed map.
An ultrasound diagnostic apparatus using an ultrasound image has hitherto been put into practical use in the field of medicine. In general, this type of ultrasound diagnostic apparatus has an ultrasound probe equipped with a transducer array and an apparatus body connected to the ultrasound probe. An ultrasonic beam is transmitted from the ultrasound probe toward a subject, an ultrasonic echo from the subject is received by the ultrasound probe, and the reception signal is electrically processed by the apparatus body to produce an ultrasound image.
In recent years, in order to diagnose a region under diagnosis in the subject with greater precision, the sound speed in the region under diagnosis is measured.
For example, JP 2010-99452 A describes an ultrasound diagnostic apparatus which sets a plurality of lattice points in the vicinity of the region under diagnosis, and a local sound speed value is calculated on the basis of reception data obtained by transmitting and receiving an ultrasonic beam for each lattice point.
In the apparatus described in JP 2010-99452 A, the ultrasonic beam is transmitted from the ultrasound probe toward the subject and received by the ultrasound probe to calculate the local sound speed value in the region under diagnosis, making it possible to display information of the local sound speed on the B-mode image in an overlapping manner. If a sound speed map which represents the distribution of the local sound speed values at a plurality of points in a predetermined region is produced and displayed along with a B-mode image, it is effective to diagnose the region under diagnosis.
In order to calculate a more accurate local sound speed value, an ultrasonic beam is transmitted such that, compared to production of a B-mode image, a transmission focus is targeted to each of a plurality of lattice points set in the vicinity of the region under diagnosis, and an ultrasonic echo is transmitted through a wide opening. For this reason, it is preferable that a transducer array which is used for sound speed map production be provided separately from a transducer array which is used for B-mode image production.
However, if both a transducer array for a B-mode image and a transducer array for a sound speed map are disposed in a subject abutment portion of the ultrasound probe, a subject abutment portion has a large area, and operational performance when the subject abutment portion of the ultrasound probe is pressed against the body surface of the subject may be deteriorated.